Drinking on the tube - adverts

I was at Euston the other day, where they've been experimenting with the moving, silent adverts beamed across the track to the facing wall.

Out of the three rolling adverts though, two were for alcohol - Stella (!) and Magners:

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Not that I've got anything against this at all, and I'd love England to become more laid-back about alcohol like in Europe, but:

a) isn't advertising alcohol on the tv before 9pm banned anyway? I know this isn't the tv, but even so it's fairly similar. Would this fall under similar legislation?
b) isn't drinking on the tube a bit of a contentious issue anyway - after the Circle Line party, etc. I wouldn't have thought 'they' would have been too keen to be showing adverts for beer/cider for fear of condoning/encouraging it.

Again, I'm not saying these adverts are particularly a bad thing, just interesting given the above points...

btw, sorry if these images are too big (are they?), not sure what the rules are on this. Michael